Fermentation processes are used for making a vast number of commercial products, including alcohols (e.g., ethanol, methanol, butanol); organic acids (e.g., citric acid, acetic acid, itaconic acid, lactic acid, gluconic acid); ketones (e.g., acetone); amino acids (e.g., glutamic acid); gases (e.g., H2 and CO2), and more complex compounds, including, for example, antibiotics (e.g., penicillin and tetracycline); enzymes; vitamins (e.g., riboflavin, B12, beta-carotene); hormones, and other compounds which are difficult to produce synthetically. Fermentation processes are also commonly used in the consumable alcohol industry (e.g., beer and wine), dairy industry (e.g., in the production of yogurt and cheese), leather industry, and tobacco industry.
There is a need for further improvement of fermentation processes and for improved processes which include a fermentation step.